If memory serves, McCain & Palin got 4% of the black vote and 55% of the white vote. Obama/Biden got 95% of black votes, and about 43% of white voters. But it's not all due to race on the part of black voters. Blacks vote by politics, just like white voters do. They'll vote for a white liberal over a black conservative every time. How many blacks ever voted for Alan Keyes?
BTW: I'm no fan of AA. It had noble intentions, but its execution has been problematic and has lead to much resentment and ill-will. I actually think reparations for past racial discrimination should be considered. Living citizens of all racial minorities that have faced unfair treatment--blacks, Asians, American Indians--will be paid a lump sum. And in return, all mandatory AA programs will be terminated. Maybe we can get this behind us once and for all. I know the mechanics could be nightmarish, but why not think about it?